It does seem odd that the owner of a business that thrives on selling used gear would make the statements about dd attributed to him by Henry or Henry's source. Based on the results of my Google search, those Denon chips seem to be available all over Hong Kong, if he would stick his head out of his door. C'est la vie.
This is what I was alluding to in the synth world- its a bid, based on fear, for a higher price- maybe for the cost of repair (replacing an 'expensive' chip that you don't have to replace, but get to make money on), being unwilling to admit to not being able to repair the unit, that sort of thing.
Bottom line is chip failure is the least of your concerns! They literally will be the least likely thing to fail.